Draft California 2020 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 9 - San Diego Region

Water Body Name: Loma Alta Slough
Water Body ID: CAE9041000019991117150520
Water Body Type: Estuary
 
DECISION ID
127886
Region 9     
Loma Alta Slough
 
Pollutant: Indicator Bacteria
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)(2018)
Revision Status Revised
Sources: Urban Runoff/Storm Sewers
Expected TMDL Completion Date: 2027
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the section 303(d) list under section 4.3 of the Listing Policy. Under section 4.3 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Three of the three samples exceed the GM threshold for Enterococci.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Three of three samples exceeded the Enterococci water quality threshold for the protection of REC-1, and this is insufficient information in Table 4.2 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the salinity level of this waterbody is greater than 1 part per thousand more than 5 percent of the time, the enterococci bacteria objective applies Therefore, this waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using the enterococci objective.

In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy.

For enterococci data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches or inland surface waters from April 1 through October 31 only, and where collected from inland waters from April 1 through October 31 only, bacterial measurements must be indicative of human fecal matter, and there is substantial human contact in the waterbody.

No fecal coliform data are used in this assessment because the fecal coliform water quality objective was superseded and is no longer used as the basis of any 303(d) List decision for water contact recreation.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation: The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the salinity level of this waterbody is greater than 1 part per thousand more than 5 percent of the time, the enterococci bacteria objective applies Therefore, this waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using the enterococci objective.

In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy.

For enterococci data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches or inland surface waters from April 1 through October 31 only, and where collected from inland waters from April 1 through October 31 only, bacterial measurements must be indicative of human fecal matter, and there is substantial human contact in the waterbody.

No fecal coliform data are used in this assessment because the fecal coliform water quality objective was superseded and is no longer used as the basis of any 303(d) List decision for water contact recreation.
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 220643
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 11
Number of Exceedances: 11
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Loma Alta Slough to determine beneficial use support and the results are as follows: 11 of the 11 samples exceeded the Statistical Threshold Value (STV) water quality threshold for Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Water data for the 2020/2022 integrated report in Region 9.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial for all saline waters, is a Statistical Threshold Value (STV) of Enterococci of 110 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): LA-PSB
Temporal Representation: The samples were collected between the days of 2016-05-03 and 2017-04-04 .
Environmental Conditions:
QAPP Information: Weston Solutions, Inc.. 2016. Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek.
QAPP Information Reference(s): Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 27137
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 186
Number of Exceedances: 7
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from Januray 2004 through December 2007. A total of 186 single samples were collected with 7 samples exceeding the single sample water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Enterococcus density shall not exceed 104 per 100 ml;

Geomean: Enterococcus density shall not exceed 35 per 100 ml (SWRCB, 2005).
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected from January 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 30542
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 171
Number of Exceedances: 1
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from Januray 2004 through December 2007. A total of 186 single samples were collected of which 171 are dry weather (AB411) samples and one sample exceeded the single sample water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Enterococcus density shall not exceed 104 per 100 ml;

Geomean: Enterococcus density shall not exceed 35 per 100 ml (SWRCB, 2005).
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected from January 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 27142
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 34
Number of Exceedances: 1
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from January 2004 through December 2007. A total of 186 single samples were collected with 34 monthly geomeans calculated. Only one of the 34 geomeans exceed the geomean water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Enterococcus density shall not exceed 104 per 100 ml;

Geomean: Enterococcus density shall not exceed 35 per 100 ml (SWRCB, 2005).
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected from January 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 31337
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 25
Number of Exceedances: 1
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from June 2004 through October 2007. A total of 103 dry month (April through October) single samples were collected with 25 dry month geomeans calculated. One of the 25 geomeans exceeded the geomean water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Enterococcus density shall not exceed 104 per 100 ml;

Geomean: Enterococcus density shall not exceed 35 per 100 ml (SWRCB, 2005).
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected from June 2004 through October 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 27140
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 15
Number of Exceedances: 6
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from October 2004 through December 2007. A total of 186 single samples were collected with 15 samples correlated with a storm event. Six of the 15 single samples exceeded the single sample water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
  National Weather Service Forecast Office, San Diego, California, Chronological Regional Temperature and Precipitation Listings by Station
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Enterococcus density shall not exceed 104 per 100 ml;

Geomean: Enterococcus density shall not exceed 35 per 100 ml (SWRCB, 2005).

Comparisons to water quality objectives were made for all data and data associated with storm events. A storm event was defined as 0.2 inches of rainfall within a 72 hour period.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected from October 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 27136
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 34
Number of Exceedances: 0
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from Januray 2004 through December 2007. A total of 186 single samples were collected with 34 geomeans calculated. None of the geomeans exceeded the geomean water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Fecal coliform density shall not exceed 400 per 100 ml;

Geomean: Fecal coliform density shall not exceed 200 per 100ml (SWRCB, 2005).
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected from January 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 31338
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 25
Number of Exceedances: 0
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from June 2004 through October 2007. A total of 103 dry month (April through October) single samples were collected with 25 dry month geomeans calculated. None of the 25 geomeans exceeded the geomean water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Fecal coliform density shall not exceed 400 per 100 ml;

Geomean: Fecal coliform density shall not exceed 200 per 100ml (SWRCB, 2005).
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected from June 2004 through October 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 27110
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 186
Number of Exceedances: 7
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from January 2004 through December 2007. A total of 186 single samples were collected with 7 samples exceeding the single sample water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Fecal coliform density shall not exceed 400 per 100 ml;

Geomean: Fecal coliform density shall not exceed 200 per 100ml (SWRCB, 2005).
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected from January 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 27122
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 15
Number of Exceedances: 5
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from January 2004 through December 2007. A total of 186 single samples were collected with 15 samples correlated with a storm event. Five of the samples exceeded the single sample water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
  National Weather Service Forecast Office, San Diego, California, Chronological Regional Temperature and Precipitation Listings by Station
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Fecal coliform density shall not exceed 400 per 100 ml;

Geomean: Fecal coliform density shall not exceed 200 per 100ml (SWRCB, 2005).

Comparisons to water quality objectives were made for all data and data associated with storm events. A storm event was defined as 0.2 inches of rainfall within a 72 hour period.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected from January 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 26879
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 15
Number of Exceedances: 7
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from January 2004 through December 2006. A total of 15 single samples were collected with 12 samples correlated with a storm event. From the 12 samples only one exceeded single sample water quality objective.
Data Reference: The National Pollutant Discharge Elimination System (NPDES) Municipal Stormwater Permit, Coastal Storm Drain Outfall Program. Bacteria Shoreline Data. 2002 through 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: From the Ocean Plan the median coliform density shall not exceed 70 per 100ml, and not more than 10 percent of the samples shall exceed 230 per 100ml (SWRCB, 2005).

Comparisons were made for all data and data associated with storm events. A storm event was defined as 0.2 inches of rainfall within a 72 hour period.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected one to five times annually for a period of three years from October 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion of this study was conducted in accordance with the County of San Diego Quality Assessment/Quality Control document.
QAPP Information Reference(s): County of Orange. Quality Assurance/Quality Control Manual, February 2004 Bacteria specific
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 4455
 
Pollutant: Indicator Bacteria
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 31339
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 25
Number of Exceedances: 0
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from June 2004 through October 2007. A total of 103 dry month (April through October) single samples were collected with 25 dry month geomeans calculated. None of the 25 geomeans exceeded the geomean water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
  National Weather Service Forecast Office, San Diego, California, Chronological Regional Temperature and Precipitation Listings by Station
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Geomean: Total coliform density shall not exceed 1,000 per 100ml (SWRCB, 2005).

Single Sample Maximum: Total coliform density shall not exceed 10,000 per 100ml;
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected weekly from June 2004 through October 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion of this study was conducted in accordance with the County of San Diego's Quality beach monitoring program.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 27055
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 186
Number of Exceedances: 0
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Shoreline beach monitoring data was collected by the County of San Diego from June 2004 through December 2007. The number of samples collected for total coliform analysis was 186 with 34 monthly geomeans calculated. None of the geomeans exceeded the geomean water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
  National Weather Service Forecast Office, San Diego, California, Chronological Regional Temperature and Precipitation Listings by Station
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Geomean: Total coliform density shall not exceed 1,000 per 100ml (SWRCB, 2005).

Single Sample Maximum: Total coliform density shall not exceed 10,000 per 100ml;
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected weekly from January 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion of this study was conducted in accordance with the County of San Diego's Quality beach monitoring program.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 26903
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 34
Number of Exceedances: 0
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Shoreline beach monitoring data was collected by the County of San Diego from June 2004 through October 2007. The number of samples collected for total coliform analysis was 186. None of the 34 samples exceeded the single sample geomean maximum total coliform standard.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
  National Weather Service Forecast Office, San Diego, California, Chronological Regional Temperature and Precipitation Listings by Station
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Geomean: Total coliform density shall not exceed 1,000 per 100ml (SWRCB, 2005).
Single Sample Maximum: Total coliform density shall not exceed 10,000 per 100ml;
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected almost monthly from January 2004 through October 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion of this study was conducted in accordance with the County of San Diego's Quality beach monitoring program.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 27138
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 34
Number of Exceedances: 1
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Beach monitoring data was collected by the County of San Diego from Januray 2004 through December 2007. A total of 186 single samples were collected with 34 monthly geomeans calculated. Only one of the 34 geomeans exceed the geomean water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Single Sample Maximum: Enterococcus density shall not exceed 104 per 100 ml;

Geomean: Enterococcus density shall not exceed 35 per 100 ml (SWRCB, 2005).
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected 500 feet north of the Loma Alta Slough outlet.
Temporal Representation: Samples were collected from January 2004 through December 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion was conducted in accordance with the County of San Diego, Department Public Health Laboratory Quality Assurance Manual.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 220653
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 3
Number of Exceedances: 3
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Loma Alta Slough to determine beneficial use support and the results are as follows: 3 of the 3 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly.
Data Reference: Water data for the 2020/2022 integrated report in Region 9.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial for all saline waters, is a geometric mean (GM) of Enterococci not to exceed 30 cfu/100 mL. The waterbody GM shall not be greater than the applicable GM magnitude in any six-week interval, calculated weekly (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): LA-PSB
Temporal Representation: The samples were collected between the days of 2016-05-03 and 2017-04-04 .
Environmental Conditions:
QAPP Information: Weston Solutions, Inc.. 2016. Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek.
QAPP Information Reference(s): Quality Assurance Project Plan Microbial Source Identification Study for Buccaneer Beach and Loma Alta Creek
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 26902
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 134
Number of Exceedances: 15
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Shoreline beach monitoring data was collected by the County of San Diego from June 2004 through October 2007. The number of samples collected for total coliform analysis was 134. Of the 134 samples, 15 exceeded the single sample maximum total coliform standard for shellfish harvesting.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: From the Ocean Plan, the median total coliform density shall not exceed 70 per 100 ml, and not more than 10 percent of the samples shall exceed 230 per 100 ml.
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected weekly from June 2004 through October 2007.
Environmental Conditions:
QAPP Information: Quality control for the bacteria analysis portion of this study was conducted in accordance with the County of San Diego's Quality beach monitoring program.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
Line of Evidence (LOE) for Decision ID 127886, Indicator Bacteria
Region 9     
Loma Alta Slough
 
LOE ID: 27061
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 15
Number of Exceedances: 3
 
Data and Information Type: PWS pathogen monitoring (ambient water)
Data Used to Assess Water Quality: Shoreline beach monitoring data was collected by the County of San Diego from June 2004 through December 2007. The number of samples collected for total coliform analysis was 186 with 15 samples correlated with a storm event. Only 3 of the 15 samples exceeded the single sample water quality objective.
Data Reference: Department of Environmental Health, Ocean & Bay Recreational Water Quality Program, 2007. AB 411 monitoring data 1999 to 2007
  National Weather Service Forecast Office, San Diego, California, Chronological Regional Temperature and Precipitation Listings by Station
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Geomean: Total coliform density shall not exceed 1,000 per 100ml (SWRCB, 2005).

Single Sample Maximum: Total coliform density shall not exceed 10,000 per 100ml;
Objective/Criterion Reference: Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Pacific Ocean Shoreline, 500 feet north of Loma Alta outlet in the Loma Alta HA.
Temporal Representation: Samples were collected weekly from June 2004 through December 2007.
Environmental Conditions: Comparisons were also made for days with matching bacteria and storm event data. A storm event was defined as 0.2 inches of rainfall within a 72 hour period.
QAPP Information: Quality control for the bacteria analysis portion of this study was conducted in accordance with the County of San Diego's Quality beach monitoring program.
QAPP Information Reference(s): County of San Diego, 2006. Department Public Health Laboratory, Quality Assurance Manual, December 2006
 
 
DECISION ID
77702
Region 9     
Loma Alta Slough
 
Pollutant: Eutrophic
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)(2016)
Revision Status Original
Sources: Urban Runoff/Storm Sewers
Expected TMDL Completion Date: 2027
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Region 9 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle.

303(d) listing decisions made prior to 2006 were not held in an assessment database. The Regional Boards will update this decision when new data and information become available and are assessed.
 
Regional Board Decision Recommendation: Region 9 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. The Regional Board will update this decision when new data and information become available and are assessed.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 77702, Eutrophic
Region 9     
Loma Alta Slough
 
LOE ID: 4454
 
Pollutant: Eutrophic
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Marine Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):